[polly] r313881 - [ScopInfo] Use map for value def/PHI read accesses.
Michael Kruse via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 21 07:23:11 PDT 2017
Author: meinersbur
Date: Thu Sep 21 07:23:11 2017
New Revision: 313881
URL: http://llvm.org/viewvc/llvm-project?rev=313881&view=rev
Log:
[ScopInfo] Use map for value def/PHI read accesses.
Before this patch, ScopInfo::getValueDef(SAI) used
getStmtFor(Instruction*) to find the MemoryAccess that writes a
MemoryKind::Value. In cases where the value is synthesizable within the
statement that defines, the instruction is not added to the statement's
instruction list, which means getStmtFor() won't return anything.
If the synthesiable instruction is not synthesiable in a different
statement (due to being defined in a loop that and ScalarEvolution
cannot derive its escape value), we still need a MemoryKind::Value
and a write to it that makes it available in the other statements.
Introduce a separate map for this purpose.
This fixes MultiSource/Benchmarks/MallocBench/cfrac where
-polly-simplify could not find the writing MemoryAccess for a use. The
write was not marked as required and consequently was removed.
Because this could in principle happen as well for PHI scalars,
add such a map for PHI reads as well.
Added:
polly/trunk/test/Simplify/notredundant_synthesizable_unknownit.ll
Modified:
polly/trunk/include/polly/ScopInfo.h
polly/trunk/lib/Analysis/ScopInfo.cpp
Modified: polly/trunk/include/polly/ScopInfo.h
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/include/polly/ScopInfo.h?rev=313881&r1=313880&r2=313881&view=diff
==============================================================================
--- polly/trunk/include/polly/ScopInfo.h (original)
+++ polly/trunk/include/polly/ScopInfo.h Thu Sep 21 07:23:11 2017
@@ -1912,6 +1912,14 @@ private:
/// A number that uniquely represents a Scop within its function
const int ID;
+ /// Map of values to the MemoryAccess that writes its definition.
+ ///
+ /// There must be at most one definition per llvm::Instruction in a SCoP.
+ DenseMap<Value *, MemoryAccess *> ValueDefAccs;
+
+ /// Map of values to the MemoryAccess that reads a PHI.
+ DenseMap<PHINode *, MemoryAccess *> PHIReadAccs;
+
/// List of all uses (i.e. read MemoryAccesses) for a MemoryKind::Value
/// scalar.
DenseMap<const ScopArrayInfo *, SmallVector<MemoryAccess *, 4>> ValueUseAccs;
@@ -2392,6 +2400,18 @@ public:
/// created in this pass.
void addAccessFunction(MemoryAccess *Access) {
AccessFunctions.emplace_back(Access);
+
+ // Register value definitions.
+ if (Access->isWrite() && Access->isOriginalValueKind()) {
+ assert(!ValueDefAccs.count(Access->getAccessValue()) &&
+ "there can be just one definition per value");
+ ValueDefAccs[Access->getAccessValue()] = Access;
+ } else if (Access->isRead() && Access->isOriginalPHIKind()) {
+ PHINode *PHI = cast<PHINode>(Access->getAccessInstruction());
+ assert(!PHIReadAccs.count(PHI) &&
+ "there can be just one PHI read per PHINode");
+ PHIReadAccs[PHI] = Access;
+ }
}
/// Add metadata for @p Access.
Modified: polly/trunk/lib/Analysis/ScopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopInfo.cpp?rev=313881&r1=313880&r2=313881&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopInfo.cpp (original)
+++ polly/trunk/lib/Analysis/ScopInfo.cpp Thu Sep 21 07:23:11 2017
@@ -4914,9 +4914,14 @@ void Scop::addAccessData(MemoryAccess *A
}
void Scop::removeAccessData(MemoryAccess *Access) {
- if (Access->isOriginalValueKind() && Access->isRead()) {
+ if (Access->isOriginalValueKind() && Access->isWrite()) {
+ ValueDefAccs.erase(Access->getAccessValue());
+ } else if (Access->isOriginalValueKind() && Access->isRead()) {
auto &Uses = ValueUseAccs[Access->getScopArrayInfo()];
std::remove(Uses.begin(), Uses.end(), Access);
+ } else if (Access->isOriginalPHIKind() && Access->isRead()) {
+ PHINode *PHI = cast<PHINode>(Access->getAccessInstruction());
+ PHIReadAccs.erase(PHI);
} else if (Access->isOriginalAnyPHIKind() && Access->isWrite()) {
auto &Incomings = PHIIncomingAccs[Access->getScopArrayInfo()];
std::remove(Incomings.begin(), Incomings.end(), Access);
@@ -4930,11 +4935,7 @@ MemoryAccess *Scop::getValueDef(const Sc
if (!Val)
return nullptr;
- ScopStmt *Stmt = getStmtFor(Val);
- if (!Stmt)
- return nullptr;
-
- return Stmt->lookupValueWriteOf(Val);
+ return ValueDefAccs.lookup(Val);
}
ArrayRef<MemoryAccess *> Scop::getValueUses(const ScopArrayInfo *SAI) const {
@@ -4952,10 +4953,7 @@ MemoryAccess *Scop::getPHIRead(const Sco
return nullptr;
PHINode *PHI = cast<PHINode>(SAI->getBasePtr());
- ScopStmt *Stmt = getStmtFor(PHI);
- assert(Stmt && "PHINode must be within the SCoP");
-
- return Stmt->lookupPHIReadOf(PHI);
+ return PHIReadAccs.lookup(PHI);
}
ArrayRef<MemoryAccess *> Scop::getPHIIncomings(const ScopArrayInfo *SAI) const {
Added: polly/trunk/test/Simplify/notredundant_synthesizable_unknownit.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/Simplify/notredundant_synthesizable_unknownit.ll?rev=313881&view=auto
==============================================================================
--- polly/trunk/test/Simplify/notredundant_synthesizable_unknownit.ll (added)
+++ polly/trunk/test/Simplify/notredundant_synthesizable_unknownit.ll Thu Sep 21 07:23:11 2017
@@ -0,0 +1,65 @@
+; RUN: opt %loadPolly -polly-simplify -analyze < %s | FileCheck %s -match-full-lines
+;
+; Do not remove the scalar value write of %i.trunc in inner.for.
+; It is used by body.
+; %i.trunc is synthesizable in inner.for, so some code might think it is
+; synthesizable everywhere such that no scalar write would be needed.
+;
+; Note that -polly-simplify rightfully removes %inner.cond. It should
+; not have been added to the instruction list in the first place.
+;
+define void @func(i32 %n, i32* noalias nonnull %A) {
+entry:
+ br label %for
+
+for:
+ %j = phi i32 [0, %entry], [%j.inc, %inc]
+ %j.cmp = icmp slt i32 %j, %n
+ %zero = sext i32 0 to i64
+ br i1 %j.cmp, label %inner.for, label %exit
+
+
+ ; This loop has some unusual properties:
+ ; * It has a known iteration count (8), therefore SCoP-compatible.
+ ; * %i.trunc is synthesizable within the loop ({1,+,1}<%while.body>).
+ ; * %i.trunc is not synthesizable outside of the loop, because its value is
+ ; unknown when exiting.
+ ; (should be 8, but ScalarEvolution currently seems unable to derive that)
+ ;
+ ; ScalarEvolution currently seems to not able to handle the %zero.
+ ; If it becomes more intelligent, there might be other such loop constructs.
+ inner.for:
+ %i = phi i64 [%zero, %for], [%i.inc, %inner.for]
+ %i.inc = add nuw nsw i64 %i, 1
+ %i.trunc = trunc i64 %i.inc to i32
+ %i.and = and i32 %i.trunc, 7
+ %inner.cond = icmp eq i32 %i.and, 0
+ br i1 %inner.cond, label %body, label %inner.for
+
+ body:
+ store i32 %i.trunc, i32* %A
+ br label %inc
+
+
+inc:
+ %j.inc = add nuw nsw i32 %j, 1
+ br label %for
+
+exit:
+ br label %return
+
+return:
+ ret void
+}
+
+
+; CHECK: After accesses {
+; CHECK-NEXT: Stmt_inner_for
+; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 1]
+; CHECK-NEXT: [n] -> { Stmt_inner_for[i0, i1] -> MemRef_i_trunc[] };
+; CHECK-NEXT: Stmt_body
+; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT: [n] -> { Stmt_body[i0] -> MemRef_A[0] };
+; CHECK-NEXT: ReadAccess := [Reduction Type: NONE] [Scalar: 1]
+; CHECK-NEXT: [n] -> { Stmt_body[i0] -> MemRef_i_trunc[] };
+; CHECK-NEXT: }
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